Net preambles give a continuity to the net and follows net protocol to make it easier for the NCO to follow. This also gives the operator in the field a good feel of what is going on, a key when to really pay attention for important information that may have been missed previously, etc. Formal nets need to have preambles and a protocol to follow, that is passed on from one net control operator to the next during shift changes and breaks to assure the net continues to run smoothly.